Moog Music Forum

I've been using one of my expression pedals as gate trigger on my little phatty. Now it works only as on/off trigger on gate cv and has no effect on any other cv.

Any idea what happened to my EP-2?

No clue. Expression pedals are simple devices, containing only a pot. You can not damage it under regular use. Something else must be the matter, although there's always the possibility of defective wiring inside the pedal.

I believe "gate" is an on-off parameter, usually triggered by the press of a key. For a gradual beginning, adjust the attack, or use the EP for volume.

The EP-2 has two potentiometers in series and nothing else.

Voltage comes into the pedal via the ring connection on the jack. It's attenuated by the pot mounted externally so that you can adjust the top end of the return, then goes into the interior pot which spins based on toe/heel position.

So if you have the attenuation down to say, 50%, then of the 5V that originated at the Phatty or a MoogerFooger's jack, the output of the EP-2 will be approximately 0 to 2.5V.

I say approximately because the string bit is rather imprecise and there is also tolerance within the pots of possibly 5% or 10% or more all depending.

But that's it, not other comments, no ICs, op amps, caps, resistors, etc.

Using an EP-2 as a Gate pedal is a bit peculiar simply because most trigger circuits need to see a sharp rise in voltage in within a few ms. To do this (depending on the device), you need to stomp on the EP-2. And Stomping on an EP-2 will certainly cause the string to slip up. The new EP-3 is cam driven so it's much higher build quality.

If you are handy, it wouldn't be a bad idea to remove the bottom plate and see how it looks inside; If you are not handy, you should take a voltmeter and measure the output voltage (on tip) after supplying 6V to the Ring/Ground. Note that I say 6V because it's easy to get either a dry cell or line up 4 x 1.5V batteries. Or a handy dandy unused power supply with a few wires.

It's not rocket science but the interior of that pedal is a bit finickiy; there is a rotating cylinder with knurled grip and a string that wraps around it, a spring to keep tension on, and a few wires.

I wouldn't be surprised to see that the string slipped and you are only controlling the upper range of the pedal now. Be sure that the pot on the side is set properly as well. It's all very subjective because if the device (Phatty in this case) is happy enough to see the voltage as Gate, it must be moving; but perhaps not enough to make discernible change on another CV connection.